Birds of a Feather recounts the story of Roy and Silo, the two Central Park Zoo chinstrap penguins who partnered, adopted an egg, hatched and raised a chick together. Roy and Silo are no strangers to the spotlight. In 2005, they were the subject of a widely contested children's book, And Tango Makes Three, by Peter Parnell and Justin Richardson. The book, temporarily pulled from school bookshelves in Loudoun County, became one of the most banned books in the US.